Evidence for A Weakening Relationship between Interannual Temperature Variability and Northern Vegetation Activity
Shilong Piao1, Huijuan Nan2, Chris Huntingford3, Philippe Ciais4, Pierre Friedlingstein5, Stephen Sitch5, Shushi Peng6, Anders Ahlström7, Josep Gili Canadell8, Nan Cong2, Sam Levis9, Peter E. Levy10, Lingli Liu11, Mark Lomas12, Jiafu Mao13, Ranga Myneni14, Philippe P Peylin6, Benjamin Poulter15, Xiaoying Shi16, Guodong Yin2, Nicolas Viovy6, Tao Wang17, Xuhui Wang6, Soenke Zaehle18, Ning Zeng19, Zhenzhong Zeng20 and Anping Chen21, (1)Peking University, Institute of Carbon Neutrality, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Beijing, China, (2)Peking University, Beijing, China, (3)Centre for Ecology and Hydrology, Wallingford, United Kingdom, (4)LSCE Laboratoire des Sciences du Climat et de l'Environnement, Gif-Sur-Yvette, France, (5)University of Exeter, Faculty of Environment, Science and Economy, Exeter, United Kingdom, (6)CEA Saclay DSM / LSCE, Gif sur Yvette, France, (7)Lund University, Physical Geography and Ecosystem Science, Lund, Sweden, (8)CSIRO Ocean and Atmosphere, Canberra, ACT, Australia, (9)National Center for Atmospheric Research, Boulder, United States, (10)Center for Ecology and Hydrology Penicuik, Penicuik, United Kingdom, (11)IB Institute of Botany, Chinese Academy of Sciences, Beijing, China, (12)Leverhulme Centre for Climate Change Mitigation, Leverhulme Centre for Climate Change Mitigation, Sheffield, United Kingdom, (13)Oak Ridge National Laboratory, Environmental Sciences Division, Oak Ridge, TN, United States, (14)Boston University, Earth and Environment, Boston, MA, United States, (15)NASA GSFC, Biospheric Sciences, Greenbelt, United States, (16)Oak Ridge National Laboratory, Oak Ridge, United States, (17)Institut Pierre Simon Laplace, Paris, France, (18)Max Planck Institute for Biogeochemistry, Biogeochemical Signals, Jena, Germany, (19)University of Maryland, College Park, MD, United States, (20)Peking University, School of Environmental Science and Engineering, Beijing, China, (21)Colorado State University, Fort Collins, CO, United States
Abstract:
Satellite derived Normalized Difference Vegetation Index (NDVI), a proxy of vegetation productivity, is known to be correlated with temperature in northern ecosystems. Here we show that above 30 oN, the strength of the relationship between the interannual variability of growing season NDVI and temperature (partial correlation coefficient RNDVI-GT) has declined substantially between 1982 and 2011, although with a heterogeneous spatial pattern. This decrease of RNDVI-GT is mainly observed in temperate and arctic ecosystems, and this phenomenon also partly reproduced by process-based ecosystem model results. In the northern temperate zone, the decrease of RNDVI-GT coincides with an increase of drought. In the arctic it may be related to a nonlinear response of photosynthesis to temperature, increase of hot extreme days, and shrub expansion over grass-dominated tundra. Our results caution the use of results from interannual time scales to constrain decadal response of plants to ongoing warming.
